LAUSR

'The Hagfeldt donor' is a bulky triarylamine building block with 4 alkyl chains in a 3-dimensional arrangement which is used with organic dyes in dye-sensitized solar cells (DSCs) in over 140 manuscripts. Many of the highest performing DSC devices in literature make use of this group due to exceptional TiO2 surface protection properties which slows recombination of electrons in TiO2 with the electrolyte. Importantly, record-setting cobalt and copper redox shuttle based-DSCs require exceptional surface protection to slow a facile recombination of electrons to these positively charged redox shuttles. Several syntheses have emerged for the Hagfeldt donor due to the need for iterative aryl-halide cross couplings complicating a straight forward route. The six synthetic strategies found in literature are described along with the challenges of each route. A recent method that has been put forward in the literature as a scalable, regioisomerically pure route is highlighted.